OBJECTIVES: X-linked myotubular myopathy (XLMTM) is a rare genetic life-threatening disease characterized by early onset, severe muscle weakness and respiratory failure. Most children with XLMTM depend on permanent use of ventilation, feeding tubes, wheelchairs, and home health services. Medicaid provides coverage for XLMTM patients, but the costs paid by Medicaid for XLMTM patients have not been estimated.

METHODS: This retrospective longitudinal study used the IBM MarketScan multi-state Medicaid claims database from 1/1/2009 to 12/31/2018. An algorithm based on demographic information, diagnosis and procedure codes, and medications was used to identify probable XLMTM patients. Healthcare resource utilization (HRU) and all-cause direct medical costs paid by Medicaid were calculated. Per patient per month (PPPM) HRU and costs were stratified by patient age.

RESULTS: Among 66 patients meeting study criteria, mean age (±standard deviation [SD]) at first observable diagnosis was 0.65y±0.9; following diagnosis, patients were observable for 35.7±27.13 months, on average, with hospitalizations that were frequent (4.3±3.09 over all observable months) and lengthy (mean length of stay: 88.6d±83.7); nearly all (92%) had at least 1 intensive care unit stay. Costs were highest in the first year of life, averaging $37,250 PPPM, largely reflecting inpatient admissions ($31,538±58,331 PPPM). Costs paid by Medicaid averaged $1.156 million over the first 4 years of life, with inpatient costs decreasing and in-home care increasing proportionally. From age 1-2yrs, PPPM costs were $23,074, with inpatient admissions $11,034±9,041 and in-home care $8,980±2,383. From age 2-3yrs, costs were $17,588, with inpatient admissions $4,126±2,786 PPPM, and in-home care $9,919 PPPM±2,123. From age 3-4yrs, total PPPM costs were $18,459; inpatient admissions were $7,102±3,782, and in-home care $8,286±1,825.

CONCLUSIONS: There is substantial economic burden to Medicaid imposed by XLMTM, with considerable inpatient admissions and home health service costs. Patients diagnosed and stabilized early in life may require intensive, long-term home health care.